1 .. SPDX-License-Identifier: GPL-2.0
2
3 Philips webcams (pwc driver)
4 ============================
5
6 This file contains some additional information
7 E-mail: webcam@smcc.demon.nl
8 Site: http://www.smcc.demon.nl/webcam/
9
10 As of this moment, the following cameras are s
11
12 * Philips PCA645
13 * Philips PCA646
14 * Philips PCVC675
15 * Philips PCVC680
16 * Philips PCVC690
17 * Philips PCVC720/40
18 * Philips PCVC730
19 * Philips PCVC740
20 * Philips PCVC750
21 * Askey VC010
22 * Creative Labs Webcam 5
23 * Creative Labs Webcam Pro Ex
24 * Logitech QuickCam 3000 Pro
25 * Logitech QuickCam 4000 Pro
26 * Logitech QuickCam Notebook Pro
27 * Logitech QuickCam Zoom
28 * Logitech QuickCam Orbit
29 * Logitech QuickCam Sphere
30 * Samsung MPC-C10
31 * Samsung MPC-C30
32 * Sotec Afina Eye
33 * AME CU-001
34 * Visionite VCS-UM100
35 * Visionite VCS-UC300
36
37 The main webpage for the Philips driver is at
38 a lot of extra information, a FAQ, and the bin
39 contains decompression routines that allow you
40 framerates; in addition the webcam uses less b
41 if you want to run more than 1 camera simultan
42 under a NDA, and may therefore not be distribu
43 is completely optional.
44
45 You can build this code either into your kerne
46 the latter, since it makes troubleshooting a l
47 microphone is supported through the USB Audio
48
49 When you load the module you can set some defa
50 camera; some programs depend on a particular i
51 don't know how to set it properly in the drive
52
53 size
54 Can be one of 'sqcif', 'qsif', 'qcif', 'sif
55 'vga', for an image size of resp. 128x96, 1
56 320x240, 352x288 and 640x480 (of course, on
57 support these resolutions).
58
59 fps
60 Specifies the desired framerate. Is an inte
61
62 fbufs
63 This parameter specifies the number of inte
64 frames from the cam. This will help if the
65 the cam is a bit slow or momentarily busy.
66 only introduces lag, so choose carefully. T
67 reasonable. You can set it between 2 and 5.
68
69 mbufs
70 This is an integer between 1 and 10. It wil
71 buffers to reserve for mmap(), VIDIOCCGMBUF
72 The default is 2, which is adequate for mos
73 buffering).
74
75 Should you experience a lot of 'Dumping fra
76 grabbing with a tool that uses mmap(), you
77 However, it doesn't really buffer images, i
78 slack when your program is behind. But you
79 forked program to really take advantage of
80
81 The absolute maximum is 10, but don't set i
82 up 460 KB of RAM, so unless you have a lot
83 something more than 4 is an absolute waste.
84 allocated during open(), so nothing is wast
85 use.
86
87 power_save
88 When power_save is enabled (set to 1), the
89 the cam on close() and re-activate on open(
90 turn off the LED. Not all cameras support t
91 don't have power saving at all), and some m
92 will shut down, but never wake up). Conside
93 default this option is disabled.
94
95 compression (only useful with the plugin)
96 With this option you can control the compre
97 uses to squeeze the image through the USB b
98 parameter between 0 and 3::
99
100 0 = prefer uncompressed images; if the re
101 in an uncompressed format, the driver
102 compression.
103 1 = low compression.
104 2 = medium compression.
105 3 = high compression.
106
107 High compression takes less bandwidth of co
108 introduce some unwanted artefacts. The defa
109 See the FAQ on the website for an overview
110 compression.
111
112 The compression parameter does not apply to
113 and OEM models derived from those (only a f
114 parameter.
115
116 leds
117 This settings takes 2 integers, that define
118 (in milliseconds). One of the interesting t
119 this is let the LED blink while the camera
120
121 leds=500,500
122
123 will blink the LED once every second. But w
124
125 leds=0,0
126
127 the LED never goes on, making it suitable f
128
129 By default the camera's LED is on solid whi
130 when the camera is not used anymore.
131
132 This parameter works only with the ToUCam r
133 750) and OEMs. For other cameras this comma
134 the LED cannot be controlled.
135
136 Finally: this parameters does not take effe
137 open the camera device. Until then, the LED
138
139 dev_hint
140 A long standing problem with USB devices is
141 never know what device a camera gets assign
142 order, the hub configuration, the order in
143 and the phase of the moon (i.e. it can be r
144 can give the driver a hint as to what video
145 should use with a specific camera. This is
146 cameras of the same model.
147
148 A camera is specified by its type (the numb
149 like PCA645, PCVC750VC, etc) and optionally
150 in /sys/kernel/debug/usb/devices). A hint c
151 following format::
152
153 [type[.serialnumber]:]node
154
155 The square brackets mean that both the type
156 optional, but a serialnumber cannot be spec
157 would be rather pointless). The serialnumbe
158 by a '.'; the node number by a ':'.
159
160 This somewhat cryptic syntax is best explai
161
162 dev_hint=3,5 The first detec
163 /dev/video3, th
164 other cameras w
165 available slot
166
167 dev_hint=645:1,680:2 The PCA645 came
168 and a PCVC680 /
169
170 dev_hint=645.0123:3,645.4567:0 The PC
171 0123 g
172 camera
173 gets /
174
175 dev_hint=750:1,4,5,6 The PCVC750 ca
176 next 3 Philips
177 through /dev/v
178
179 Some points worth knowing:
180
181 - Serialnumbers are case sensitive and must
182 leading zeroes (it's treated as a string)
183 - If a device node is already occupied, reg
184 the webcam is not available.
185 - You can have up to 64 video devices; be s
186 nodes in /dev if you want to spread the n
187 After /dev/video9 comes /dev/video10 (not
188 - If a camera does not match any dev_hint,
189 the first available device node, just as
190
191 trace
192 In order to better detect problems, it is n
193 'trace' of some of the calls the module mak
194 kernel log at debug level.
195
196 The trace variable is a bitmask; each bit r
197 If you want to trace something, look up the
198 below, add the values together and supply t
199
200 ====== ======= ============================
201 Value Value Description
202 (dec) (hex)
203 ====== ======= ============================
204 1 0x1 Module initialization; this
205 while loading and unloading
206
207 2 0x2 probe() and disconnect() tra
208
209 4 0x4 Trace open() and close() cal
210
211 8 0x8 read(), mmap() and associate
212
213 16 0x10 Memory allocation of buffers
214
215 32 0x20 Showing underflow, overflow
216 messages
217
218 64 0x40 Show viewport and image size
219
220 128 0x80 PWCX debugging
221 ====== ======= ============================
222
223 For example, to trace the open() & read() f
224 so you would supply trace=12 during insmod
225 you want to turn the initialization and pro
226 The default value for trace is 35 (0x23).
227
228
229
230 Example::
231
232 # modprobe pwc size=cif fps=15 power_save
233
234 The fbufs, mbufs and trace parameters are glob
235 cameras. Each camera has its own set of buffer
236
237 size and fps only specify defaults when you op
238 accommodate some tools that don't set the size
239 settings after open() with the Video4Linux ioc
240 defaults is QCIF size at 10 fps.
241
242 The compression parameter is semiglobal; it se
243 preference for all camera's, but this paramete
244 the VIDIOCPWCSCQUAL ioctl() call.
245
246 All parameters are optional.
247
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